In general both omega 3 and omega 6 are found in higher amounts in fatty fish, which neither walleye or yellow perch qualify as being examples of, as they are quite lean. Examples of fatty fish are herrings, cod and salmon/trout.
So if you want omega 3, eat wild steelhead trout, but not in excess of the consumption advisories due to PCB's, or farm-raised trout fed a diet low in omega 6 oils.
When omega 6 levels are high in farm raised fish, it's due to them being fed a diet rich in these fatty (seed) oils in their prepared fish food. Omega 6 isn't necessarily bad in itself, but in high doses, cancels out omega 3, and erases the good effects of omega 3. Nutritionists recommend a proper ratio of the two essential oils in a healthy diet.